Method and device for transmitting and receiving broadcast signal

ABSTRACT

The present invention relates to a device and a method for transmitting and receiving a signal of a broadcast including a subtitle service. One embodiment of the present invention provides a broadcast signal transmitting method comprising the steps of generating a broadcast signal, which includes video data and subtitle data, and transmitting the generated broadcast signal. According to one embodiment of the present invention, a transmission stream for providing a digital broadcasting subtitle service using XML subtitles can be transmitted.

This application is a National Stage of International Application No.PCT/KR2016/001302, filed Feb. 5, 2016 which claims the benefit of U.S.Provisional Application No. 62/114,597, filed on Feb. 11, 2015, thedisclosures of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to a device and method for transmittingand receiving broadcast signals.

BACKGROUND ART

With the development of digital technology and communication technology,a demand for and propagation of audio/video based multimedia content arerapidly increasing in various areas such as Internet and personal mediaas well as broadcast and movies. Furthermore, a consumer demand forimmersive media which provide sense of reality through broadcast andmovies is increasing. In addition, as home TV screens become large withthe development of display technology, demand for realistic content withmore than high definition (HD) is increasing. Realistic broadcastingsuch as UHDTV (Ultra High Definition TV) along with 3DTV attractsattention as a future broadcast service. Particularly, a discussionabout UHD broadcast services is increasingly conducted.

DISCLOSURE Technical Problem

An object of the present invention is to improve transmission efficiencyin a method and device for transmitting a broadcast signal.

Another object of the present invention is to provide a transmissiondevice and method for transmitting metadata for dynamically providingbrightness representation and color representation of content.

Technical Solution

A method of transmitting a broadcast signal according to an embodimentof the present invention includes: generating video data; generating abroadcast signal including the generated video data and video qualityenhancement metadata; and transmitting the generated broadcast signal.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may include high dynamic range (HDR) information or wide colorgamut (WCG) information.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the HDR information or the WCGinformation may be applied to all or some sections of the video data.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the HDR information or the WCGinformation may be applied in units of channel, program or content.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the HDR information or the WCGinformation may be applied to some sections of the video data in unitsof scene, clip or frame.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may further include synchronization information indicating astart time and duration when the HDR or the WCG information is appliedto the video data.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may further include type information indicating an applicationrange of the HDR or WCG information.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may further include signaling information indicatingtermination of application of the HDR information.

A method of receiving a broadcast signal according to an embodiment ofthe present invention includes: receiving a broadcast signal includingvideo data and video quality enhancement metadata; demultiplexing thebroadcast signal into the video data and the video quality enhancementmetadata; decoding the video data and the video quality enhancementmetadata; and applying the video quality enhancement metadata to thevideo data.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayinclude high dynamic range (HDR) information or wide color gamut (WCG)information.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the HDR information or the WCG information maybe applied to all or some sections of the video data.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the HDR information or the WCG information maybe applied in units of channel, program or content.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the HDR information or the WCG information maybe applied to some sections of the video data in units of scene, clip orframe.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayfurther include synchronization information indicating a start time andduration when the HDR or the WCG information is applied to the videodata.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayfurther include type information indicating an application range of theHDR or WCG information.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayfurther include signaling information indicating termination ofapplication of the HDR information.

A broadcast signal transmission device according to an embodiment of thepresent invention includes: an encoder for generating video data; amultiplexer for generating a broadcast signal including the generatedvideo data and video quality enhancement metadata; and a transmitter fortransmitting the generated broadcast signal.

A broadcast signal reception device according to an embodiment of thepresent invention includes: a receiver for receiving a broadcast signalincluding video data and video quality enhancement metadata; ademultiplexer for demultiplexing the broadcast signal into the videodata and the video quality enhancement metadata; a decoder for decodingthe video data and the video quality enhancement metadata; and a postprocessor for applying the video quality enhancement metadata to thevideo data.

Advantageous Effects

According to embodiments of the present invention, it is possible toimprove transmission efficiency of a broadcast system.

According to the embodiment of the present invention, a broadcastnetwork can provide dynamic luminance representation and colorrepresentation for each piece of content.

According to the embodiment of the present invention, a broadcastnetwork can provide dynamic luminance representation and colorrepresentation per scene in content.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a device that produces and reproduces a metadatabased HDR broadcast service according to an embodiment of the presentinvention.

FIG. 2 illustrates an operation method of a receiver for HDR videoaccording to an embodiment of the present invention.

FIG. 3 illustrates a post processor according to an embodiment of thepresent invention.

FIGS. 4 to 7 illustrate syntaxes of an SEI message and an HDRinformation descriptor according to an embodiment of the presentinvention.

FIGS. 8 and 9 illustrate an embodiment of signaling metadata informationaccording to RAP.

FIG. 10 illustrates dynamic_range_mapping_info according to anembodiment of the present invention.

FIG. 11 illustrates a case in which an SEI message defined in HEVC isreferred to according to an embodiment of the present invention.

FIGS. 12 and 13 illustrate an embodiment of signaling an HDR_infodescriptor according to an embodiment of the present invention through aPMT.

FIGS. 14 and 15 illustrate an embodiment of signaling the HDR_infodescriptor according to the embodiment of the present invention throughan EIT.

FIG. 16 illustrates HDR_info_descriptor( ) according to anotherembodiment of the present invention.

FIG. 17 is a block diagram of a receiver and illustrates operation ofthe receiver according to an embodiment of the present invention.

FIG. 18 is a block diagram of a broadcast transmitter according to anembodiment of the present invention.

FIG. 19 is a block diagram of a broadcast receiver according to anembodiment of the present invention.

FIG. 20 illustrates a method of transmitting a broadcast signalincluding video quality enhancement metadata according to an embodimentof the present invention.

FIG. 21 illustrates a method of receiving a broadcast signal includingvideo quality enhancement metadata according to an embodiment of thepresent invention.

BEST MODE

The present invention can provide a method for converting and presentingcontent as images with enhanced video quality by transmitting, to areceiver, a factor which can adaptively adjust the content forcharacteristics of various scenes included in the content when highdynamic range (HDR) content which can be represented in a wide range ofluminance is provided. UHD broadcast can be discriminated fromconventional broadcast and can provide high level of presence byrepresenting luminance which cannot be expressed in conventionalcontent. As a dynamic range of images increases according tointroduction of HDR (high dynamic range), a characteristic differencebetween scenes included in content may increase. Accordingly, abroadcast transmission device can additionally provide information foreffectively displaying characteristics of each scene on a display and areception device can present images through a method suitable for aproducer's intention by providing video effects on the basis of thetransmitted information.

UHD broadcast can provide enhanced video quality and immersiveness toviewers through various methods compared to HD broadcast. As one of themethods, UHD broadcast can provide a method of extending ranges ofrepresentation of luminance and color expressed in content to luminanceand color recognition ranges which can be recognized by the human visualsystem. That is, HDR (high dynamic range) and WCG (wide color gamut) canbe applied to UHD content. That is, content with enhanced contrast andcolors is provided such that a UHD content user can experience improvedimmersiveness and presence. The present invention provides a method foreffectively presenting luminance and color of images of contentdepending on intention of a producer when the content is presentedthrough a display such that a user can view images with enhanced videoquality.

FIG. 1 illustrates a device that produces and reproduces a metadatabased HDR broadcast service according to an embodiment of the presentinvention. An HDR video production device may include at least one of acapture/film scanner 101, a post-production block (mastering unit) 102and an encoder/multiplexer 103. An HDR video reproduction device mayinclude at least one of a demultiplexer 104, a decoder 105, a metadataprocessor 106, a post processor 107, a synchronizer 108 and a display109. While the figure shows metadata received by being included in avideo stream, metadata of the present invention may be transmitted andreceived through other routes (e.g., IP based broadcast/communication,wired/wireless communication, wired/wireless interfaces, short-rangewireless communication, etc.) in addition to broadcast signals.

The capture/film scanner 101 of the HDR video production device mayconvert a natural scene into digital video. For example, thecapture/film scanner may be a device that converts optical imagesobtained by a video camera, a camera, a scanner and the like intodigital images. The capture/film scanner 101 may sense an optical imageand output raw HDR (High Dynamic Range) video.

The post-production block (mastering unit) 102 may receive the raw HDRvideo and output mastered HDR video and HDR metadata. Thepost-production block may receive mastering display information, viewingcondition information, color encoding information, gamut mappinginformation and/or DR (Dynamic Range) information and perform mastering.Here, the color encoding information can be an EOTF (electro-opticaltransfer function) such as BT.2020, for example.

The encoder/multiplexer 103 may encode and multiplex at least one pieceof mastered HDR video and HDR metadata.

The demultiplexer 104 of the HDR video reproduction device may receiveand demultiplex an HDR stream. A single HDR stream may include aplurality of pieces of content. The demultiplexer may output the HDRstream corresponding to a decoding target to the decoder.

The decoder 105 may receive and decode the HDR stream. In this process,the decoder may output decoded HDR video and HDR metadata. The decodedHDR video may be output to the post processor and the HDR metadata maybe output to the metadata processor.

The metadata processor 106 may receive and store the HDR metadata. Themetadata processor may check whether the stored HDR metadata has beenchanged by checking a set number or a version number included in the HDRmetadata and update existing HDR metadata when the stored HDR metadatahas been changed. The metadata processor may output the HDR metadata tothe post processor according to timing information received from thesynchronizer.

The post processor 107 may perform post-processing on the HDR videoreceived from the decoder using the HDR metadata received from themetadata processor. Through this process, the HDR video can be convertedto enhanced HDR video in which the HDR metadata has been reflected.

The synchronizer 108 may provide timing information to the metadataprocessor and the post processor such that metadata is applied to thewhole HDR video or each scene thereof, each video clip or each frame atcorrect timing. Here, metadata may represent information about masteringdisplay or may refer to information commonly applied for a channel, aprogram and content or information applied to continuous scenes, videoclips and frames.

The HDR display 109 may display and provide the enhanced HDR video to auser.

FIG. 2 illustrates an operation method of a receiver for HDR videoaccording to an embodiment of the present invention. Although receiveroperation is mainly described in the present invention, the same detailscan be considered when related signals are generated and can be appliedto delivery signals between productions and a mastering signal.

When a video stream is received, the receiver may separate HDR metadatafrom an HDR video signal using a video decoder 201 and store theseparated HDR metadata in a separate metadata parser 202. The metadataprocessor may include a metadata parser, a metadata buffer and ametadata update unit. The HDR metadata may include common HDR metadataand scene/frame HDR metadata. The common HDR metadata is applicable toentire content and may refer to information commonly applied in units ofchannel, program and content.

The scene/frame HDR metadata may be metadata limitedly applicable topart of content and may refer to information applied to continuousscenes, video clips or frames. The receiver may determine theperformance for reproducible content type and then apply received commonHDR metadata or scene/frame HDR metadata to content and process thecontent. A receiver capable of reproducing HDR video may convert contentusing received metadata. The receiver may display the converted contentas a final image after the processing operation. A detailed receiveroperation method will be described below.

In the first step, the receiver may decode a video stream and acquireHDR metadata. The HDR metadata may refer to HDR video information(referred to as HDR_info( ) hereinafter). The receiver may deliver themetadata acquired from the video stream to the metadata parser 202,analyze the metadata and store the metadata in a memory. The metadatacan be divided into common HDR metadata and scene/frame HDR metadata. Inthe present invention, it is possible to apply the metadata according tomastering display, to commonly apply the metadata to a channel, aprogram and content or to apply the metadata to continuous scenes, videoclips and frames by delivering a range within which the metadata isapplied using type information HDR_info_type which will be describedbelow.

In addition, the metadata may further include a period to which themetadata is applied, for example, information for matching the metadatawith an applied video frame in the format of synchronization startinformation sync_start and synchronization duration informationsync_duration.

According to an embodiment, the common HDR metadata may include at leastone of a value indicating the dynamic range of content/masteringdisplay/frame, such as maximum/minimum luminance or high contrast, atransfer function such as EOTF, the color gamut of the content ormastering display, the color temperature of the content or masteringdisplay, a dynamic range transfer function, a color gamut transferfunction and viewing condition information.

In the specification, the value indicating the dynamic range of thecontent/mastering display/frame may be transmitted usingdynamic_range_info_type and dynamic_range_info_value[i]. The transferfunction such as EOTF may be transmitted using transfer_function_type.The color gamut of the content or mastering display may be transmittedusing color_gamut_type. The color temperature of the content ormastering display may be transmitted using color_temperature_type. Thedynamic range transfer function may be transmitted usingdynamic_range_mapping_info_type. The color gamut transfer function maybe transmitting using color_gamut_mapping_info_type. The viewingcondition information may be transmitted usingviewing_condition_info_type. The syntax of information and fieldsincluded therein will be described below.

The scene/frame HDR metadata may include information identical orsimilar to the common HDR metadata and may also include informationabout a range to which the scene/frame HDR metadata is applied. Thescene/frame HDR metadata can deliver more specific information becausethe range to which the scene/frame HDR metadata is applied is limited tosome parts of content. For example, the common HDR metadata can delivera dynamic range applied to entire content as a value such as f-stop orhigh contrast, whereas the scene/frame HDR metadata can deliver maximumand minimum values for a frame unit to achieve delivery of more specificinformation. Accordingly, different information delivery ranges can beapplied to steps according to types of delivered metadata. Similarly, inthe case of dynamic range mapping, information regarding transformationof overall content may be delivered as the common HDR metadata and thena complicated transfer function capable of representing characteristicsof each scene may be delivered through the scene/frame HDR metadata.

In the second step, the receiver may determine whether the displayincluded therein is an HDR display. The receiver may determine whether apresentation condition of the receiver is suitable on the basis ofinformation about the acquired content (or information about masteringdisplay) using common information. For example, the receiver may use theaforementioned common HDR metadata and may consider an SDR display or adisplay having performance between SDR and HDR if the contentpresentation condition is not suitable.

A case in which the display included in the receiver is an SDR displayor a display having performance equivalent thereto will be describedfirst. Upon determining that the receiver display cannot completelypresent decoded HDR content, the receiver may not present the HDRcontent or may perform conversion for content presentation. A receiverthat can convert HDR video into SDR video can convert received HDR videointo SDR video and present the SDR video. To this end, HDR metadata mayinclude information about a transfer function for converting HDR videointo SDR video. For example, dynamic_range_mapping_info_type orcolor_gamut_mapping_info_type may be used as the information about thetransfer function, and the HDR metadata may additionally signal use ofthe information to convert HDR video into SDR video as necessary.

Next, a case in which the display included in the receiver is an HDRdisplay will be described. This corresponds to a case in which thedisplay of the receiver is determined to be able to completely presentdecoded content. In this case, video quality can be enhanced using thecommon HDR metadata included in the HDR metadata, and video qualityenhancement can be achieved using dynamic range mapping, color gamutmapping and viewing condition mapping. According to an embodiment, videoquality enhancement for content using the common HDR metadata may beomitted when the scene/frame HDR metadata can be applied in the thirdstep which will be described below. Further, video quality enhancementusing the common HDR metadata may be realized using an additional moduleor applied in association with a post processing module which will bedescribed with reference to FIG. 3.

In the third step, the receiver may perform video quality enhancementper scene of HDR video. When it is determined that the receiver canpresent HDR content on the basis of metadata information, the receivermay determine whether the receiver can process additional HDR metadata.

FIG. 2 shows a case in which scene-by-scene (or clip-by-clip orframe-by-frame) processing is additionally performed. In this case, itis possible to display HDR video with enhanced quality through detaileddynamic conversion per scene, video clip or frame of content usingmetadata provided on a scene-by-scene or frame-by-frame basis. Here, abroadcast transmission device can cause the receiver to identifytransmission of information in units of scene or frame through asupplemental enhancement information (SEI) message using HDR_info_typeaccording to an embodiment of the present invention. Furthermore, thebroadcast transmission device can provide, to the receiver, informationabout a time at which the information in units of scene or frame needsto be applied using sync_info_type, sync_start and sync_duration. Thereceiver can identify transmission of the information in units of scene,video clip or frame through HDR_info_type and acquire timing informationabout the time at which the information in units of scene or frame isapplied through sync_info_type, sync_start and sync_duration. Inaddition, the receiver may convert the timing information providedthrough metadata into information for synchronization with images asnecessary.

In addition, the broadcast transmission device may inform the receiverof the type of metadata in units of scene, video clip or frame whichwill be provided when providing the common HDR metadata. The broadcasttransmission device may previously inform the receiver of theaforementioned information throughHDR_video_enhancement_info_present_type. That is, the receiver canacquire information about whether the scene/frame HDR metadata isreceived and the type thereof from the common HDR metadata and prepareto operate a related module. According to an embodiment, the broadcasttransmission device may indicate the fact that the metadata in units offrame, video clip or scene is provided or indicate presence ofinformation in units of frame, video clip or scene using the common HDRmetadata. For example, the broadcast transmission device can indicateprovision of dynamic range mapping and/or color gamut mappinginformation in units of frame or scene using the common HDR metadata.

According to an embodiment, the receiver may apply the common HDRmetadata and scene HDR metadata to HDR video in stages or apply the samethrough one operation. Further, the receiver may apply the common HDRmetadata and scene HDR metadata to the HDR video per dynamic rangemapping and color gamut mapping or apply the same through one transferformula.

FIG. 3 illustrates a post processor according to an embodiment of thepresent invention. In the present invention, the post processor mayinclude a dynamic range (DR) mapping block 301, a color gamut (CG)mapping block 302 and a viewing condition adjustment block 303. The postprocessor may receive HDR video data and perform video qualityenhancement using dynamic range mapping, color gamut mapping and viewingcondition mapping. The DR mapping block 301 may perform video qualityenhancement by applying dynamic range information, transfer functioninformation and DR mapping information to the input HDR video data. TheCG mapping block 302 may perform video quality enhancement by applyingcolor gamut information, color temperature information and CG mappinginformation to the input HDR video data. The viewing conditionadjustment block 303 may perform video quality enhancement by applyingviewing condition information to the HDR video data. Details of theinformation will be described below with reference to FIGS. 4 to 16.

FIGS. 4 to 7 illustrate syntaxes of an SEI message and HDR informationdescriptors according to an embodiment of the present invention.

An SEI message may include an HDR information descriptor, and the HDRinformation descriptor may include at least one of the following fields.In the present invention, HDR information may have the same meaning asHDR video information.

HDR_info_type can indicate an information application unit in the HDRinformation descriptor. For example, HDR_info_type may indicateinformation about mastering display or may be commonly applied in unitsof channel, program and content. Further, HDR_info_type may be used todiscriminate HDR information by being applied to continuous scenes,video clips or frames. Additionally, HDR information may be classifiedthrough other methods (e.g., depending on states before and afterconversion, a transmission format, a target format after conversion,static/dynamic metadata, etc.).

Types of HDR information defied in the current payloadType can bediscriminated as described above. Here, only detailed informationcorresponding to a single HDR_info_type may be described or two or morepieces of information may be described in the payloadType as in theembodiment of FIG. 4. In this case, a syntax may be configured such thatpieces of information classified in accordance with HDR_info_type arecontinuously positioned.

In addition to the method of defining an information application unit inan SEI message, the information application unit may be defined byallocating different payloadType to pieces of HDR information. Forexample, HDR information can be classified such that payloadType=52(mastering display), payloadType=53 (channel), payloadType=54 (program),payloadType=55 (content), payloadType=56 (scene), payloadType=57 (clip)and payloadType=58 (frame).

Transition_flag is a signal regarding an end time of content associatedwith an SEI message. For example, when HDR content is ended and switchedto SDR content, transition_flag is set to 1 for the last frame. This canrepresent termination of transmission of the HDR information descriptordepending on application field. The receiver may turn off a modulerelated to the HDR information descriptor on the basis of this signal.When the receiver is divided into a set-top box (STB) and a displaydevice which are connected through a wired/wireless interface (e.g.,HDMI, display port, MHL or the like), information, similar to thetransition_flag, which represents that HDR related informationtransmission is stopped or HDR content is finished may be delivered fromthe STB to the display device. The transition_flag may indicate acontent end time in a frame in which the HDR information descriptor isended. A content end time may be indicated in an RAP including an endframe if previously set.

Set_number can indicate an identification number unique to an HDRinformation descriptor. That is, when a plurality of HDR informationdescriptors is delivered in units of time or frame from the broadcasttransmission device to the receiver, the set_number can discriminate theHDR information descriptors. The set_number may discriminate a pluralityof descriptors for each of a channel, a program, content, a frame, ascene and a clip in association with the aforementioned HDR_info_type asnecessary. For example, when different DR mapping functions aredelivered in order to supply displays having various types of luminance,the set_number can discriminate a plurality of descriptors for each of achannel, a program, content, a frame, a scene and a clip in associationwith the aforementioned HDR_info_type.

Version number can indicate the version of the HDR informationdescriptor. The version_number can indicate an information change in thecurrent descriptor in association with at least one of HDR_info_type andset_number. For example, when a descriptor having the same HDR_info_typeand/or the same set_number has the same version number as the previousversion number, information in a metadata processor can be applied as itis to images. When the version_number is changed, however, the broadcastreception device can update information in a metadata buffer and applynew information to video.

DR flag (dynamic_range_mapping_info_present_flag) can indicate thatdynamic range mapping related information is included in the descriptor.

CG flag (Color_gamut_mapping_info_present_flag) can indicate that gamutmapping related information is included in the descriptor.

Viewing_condition_info present_flag can indicate that viewing conditionrelated information is included in the descriptor.

Number_of_HDR_video_enhancement_info indicates the number of pieces ofrelated information when there is an additional SEI message related tothe current SEI message. The number_of_HDR_video_enhancement_info mayprovide enhanced information. For example, when informationHDR_info_type=0011 (content) is delivered, information about masteringdisplay and scenes may be transmitted in association with thenumber_of_HDR_video_enhancement_info. In this case, thenumber_of_HDR_video_enhancement_info is 3. Here, the receiver can useonly information in content depending on performance when performingvideo quality processing such as tone mapping, gamut mapping and thelike. Furthermore, the receiver may use only information ofHDR_info_type=0100 (scene), for example, or use all informationaccording to an embodiment, upon determining that the receiver hasdetailed information.

HDR_video_enhancement_info present_type indicates the type of additionalinformation related to the current SEI message and may be defined usingthe same value as HDR_info_type of FIG. 5. Here, this information canindicate whether information related to DR mapping, gamut mapping andviewing condition is transmitted throughenh_dynamic_range_mapping_info_present_flag,enh_color_gamut_mapping_info_present_flag andenh_viewing_condition_info_present_flag and can be used when a receiveroperation for information processing is prepared or whether moreenhanced information than current information is used is determined.

Enh_dynamic_range_mapping_info_present_flag can indicate presence of DRmapping information for related metadata information when set to 1.

Enh_color_gamut_mapping_info_present_flag can indicate presence of gamutmapping information for related metadata information when set to 1.

Enh_viewing_condition_info_present_flag can indicate presence of viewingcondition information for related metadata information when set to 1.

When the metadata type is specified by a payloadType value of an SEImessage instead of HDR info, the payloadType value of the SEI messagecan be directly transmitted in addition to the aforementioned method ofusing HDR_info_type and flags related thereto. That is, payloadType=52(mastering display) and payloadType=56 (scene) can be transmitted asadditional (enhancement) information related to payloadType=53 (content)in the above example. Alternatively, payloadType may be added andprovided along with HDR_info_type.

Sync_info_type can indicate a method of representing information forsynchronization with content, scenes, clips or frames to whichinformation in the HDR information descriptor needs to be applied. Forexample, sync_info_type can deliver a picture order count (POC) valueused in a decoder or directly deliver a pic_order_count_lsb value. Inthe case of storage media, media time information can be used, and thenumber of accumulated frames on the basis of a reference time for videostart may be decided as sync_info_type.

Sync_start is information related to synchronization start time. Wheninformation is delivered in a specific period such as an RAP instead ofbeing delivered per frame, it is necessary to connect the start and endof a period in which the information is used to video frames. Thepresent invention may apply an embodiment of representing startinformation of the period or a frame to which the correspondinginformation is applied as information such as a time, a POC, the numberof frames or PTS in association with sync_info_type using sync_start.Sync_info_type can define a synchronization information type as a time,a time difference, start order, a POC (picture order count), PTS or thenumber of aggregated frames.

For example, it is possible to consider a case in which three pieces ofmetadata are applied to 2 seconds (start time), 2.5 seconds and 3.5seconds within an RAP of 2 to 4 seconds for a 50 fps video stream havingan RAP interval of 2 seconds.

When sync_info_type=0x00, the synchronization information type can beset to time and sync_start information of the metadata can be deliveredas 2000, 2500 and 3500. Additionally, sync_duration can be signaled as500, 1000 and 1000. Here, a reference time may be needed fordetermination of time. In this case, the reference time may beadditionally signaled in such a manner that a time is defined in anadaptation field of a TS header.

When sync_info_type=0x01, the synchronization information type can beset to a time difference. The broadcast transmission device can informthe receiver of immediate application of metadata, application of themetadata after 0.5 seconds from RAP and application of metadata after1.5 seconds from RAP by signaling sync_start=0, 500 and 1000.

When sync_info_type=0x02, the synchronization information type can beset to a start order and the order can be signaled like sync_start=0, 1,2. When the start order is signaled, the receiver can applysynchronization information in the order at a specific interval. Thespecific interval may be a fixed value or may be a value determined inthe order. For example, 0 can indicate immediate application, 1 canindicate application after 0.5 seconds from RAP, and 2 can indicateapplication after 1.5 seconds after RAP.

When sync_info_type=0x03, the synchronization information type can beset to a POC. In this case, 100, 125 and 175 may be delivered as POCvalues of video at metadata application timing, and 25, 50 and 50 may bedelivered as duration values which will be described below depending onthe unit of the POC. Further, values related to a POC in a video codecsyntax may be directly delivered.

When a PTS (presentation time stamp) and the number of frames aresignaled, a metadata application timing can be indicated through the PTSand the number of frames similarly to the aforementioned example of thePOC.

Sync_duration is information about a duration starting from sync_start.A synchronization expiration timing can be calculated assync_start+sync_duration as in the aforementioned example, andsynchronization expiration timing information may be directly deliveredalong with or instead of sync_duration as necessary. In the case of livebroadcast, an expiration time cannot be determined in advance and thusmay be set to a predetermined value such as FFFF. If the metadataapplication timing can be determined only with the sync_startinformation, sync_duration may not be used. In this case, sync_durationmay be used as a flag that provides additional information such asinformation indicating whether other metadata is transmitted followingthe corresponding metadata.

Number_of_dynamic_range_info can indicate the number of methods ofrepresenting dynamic range information corresponding to masteringdisplay, a channel, a program, content, a scene, a clip or a frame.

Dynamic_range_info_type indicates a method of representing dynamic rangeinformation corresponding to mastering display, video, a scene or aframe. Methods for representing a dynamic range may be as shown in thelower part of FIG. 6. Dynamic range can be represented using at leastone of maximum luminance, minimum luminance, average luminance, and anaverage or median value composed of a specific component. Further, whitemay be subdivided into normal white, diffuse white and specular whiteaccording to characteristics and black may be classified into normalblack, deep black and pitch dark according to characteristics andpresented.

As described in the example below, the broadcast transmission device cansubdivide and represent luminance of a bright part and a dark part ofcontent by providing information such as specular white and pitch darkthrough HDR info, and such information can be used as a criterion fordetermination of receiver display conditions or as information formapping according to display conditions.

A DR information value dynamic_range_info_value can deliver acorresponding value according to dynamic_range_info_type. That is,content, mastering display and scene DR can be represented in detailaccording to dynamic_range_info_type as described below. Further, the DRinformation value may be used to separately describe a container videoformat and characteristics of actual content.

Ex) Content: peak_luminance_level=2000 (nit),minimum_luminance_level=0.1 (nit)

Mastering display: peak_luminance_level=4000 (nit),minimum_luminance_level=0.01 (nit)

Scene: white_level_A=800 (nit), white_level_B=1500 (nit),black_level_A=1 (nit), black_level_B=0.1 (nit)

Transfer_function_type can indicate the type of a transfer function usedfor mastering display, a channel, a program, content, a scene, a clip ora frame of HDR video. For example, a predetermined EOTF such as SMPTE ST2084, ITU BT.1886 and BT.2020 can be signaled. Luminance representationmethods may be divided into an absolute luminance representation methodand a relative luminance representation method depending on the type ofa transfer function and a specific method may be signaled. A coefficientof an arbitrary transfer function may be delivered as necessary.

Color_gamut_type can indicate a color gamut type corresponding tomastering display, a channel, a program, content, a scene, a clip or aframe of HDR video. For example, color_gamut_type can indicate astandard color gamut such as BT.709, BT.2020 and DCI-P3 or indicate anarbitrary color gamut through RGB color primary (XYZ, RGBW and the likemay be used) as necessary.

Color_temperature_type can indicate information about standard whitecorresponding to mastering display, a channel, a program, content, ascene, a clip or a frame of a color gamut. For example,color_temperature_type may be a standard light source color temperaturesuch as D65 and D50 and may indicate an arbitrary value representativeof a color temperature such as RGB color primary (XYZ, RGBW and the likeare possible) with respect to white as necessary.

Dynamic_range_mapping_info_type indicates the type of dynamic rangemapping information corresponding to mastering display, a channel, aprogram, content, a scene, a clip or a frame. For example,dynamic_range_mapping_info_type can refer to a knee function informationSEI message or a tone mapping information SEI message included in HEVC,as shown in the upper part of FIG. 7. Furthermore,dynamic_range_mapping_info_type may be directly described in apredetermined HDR information descriptor.

Color_gamut_mapping_info_type indicates the type of color gamut mappinginformation corresponding to mastering display, a channel, a program,content, a scene, a clip or a frame. For example,color_gamut_mapping_info_type can refer to information defined in acolor remapping information SEI message included in HEVC, as shown inthe lower part of FIG. 7. Further, color_gamut_mapping_info_type may bedirectly described in a predetermined HDR information descriptor.

Viewing_condition_info_type indicates the type of viewing conditioninformation corresponding to mastering display, a channel, a program,content, a scene, a clip or a frame. For example,viewing_condition_info_type may refer to information defined inviewing_condition defined as a separate SEI message and may be directlydescribed in a predetermined HDR information descriptor.

When an external SEI message is referred to for the aforementioneddynamic_range_mapping_info_type, color_gamut_mapping_info_type andviewing_condition_info_type, a method of directly signaling payloadTypeof the SEI message may be used, distinguished from the aforementionedmethod. For example, when a knee function information SEI message isreferred to, a signaling method using dynamic_range_mapping_info_type=0and payloadType=141 may be used.

FIG. 8 illustrates a method of signaling metadata information with timeaccording to an embodiment of the present invention.

For metadata transmission with time, various methods such as 1) a methodof transmitting all of corresponding information for each frame, 2) amethod of transmitting metadata in frames corresponding to a period inwhich the metadata is changed and applied within an RAP, 3) a method ofsimultaneously transmitting metadata applied within a period such as anRAP in the period, and 4) a method of transmitting metadata prior to anRAP related to an application timing can be considered. Further, acombination of methods 1) to 4) may be used.

FIG. 8 illustrates an embodiment of signaling metadata informationaccording to RAP. The common type applied to entire video can betransmitted in each RAP. This corresponds to a case in whichHDR_info_type is set to 0000 in FIG. 8. Although the common type isrepetitive information, the broadcast transmission device can compensatefor information loss due to transmission error by transmitting thecommon type per RAP.

When information applied differently for each scene needs to beprovided, the information may be transmitted using scene metadata. Thiscorresponds to a case in which HDR_info_type is set to 0100 in FIG. 8.In this case, information corresponding to an RAP and informationapplied after scene change in the RAP can be transmitted together.Information corresponding to an RAP and information applied after scenechange in the RAP may be defined as sets having different roles and maybe discriminated from each other by being assigned different setnumbers. According to an embodiment, when pieces of information havingdifferent roles are separately delivered even though the information isapplied to the same scene, different set numbers can be used todiscriminate the information. When information is applied over two ormore RAPs, the information has the same set_number and, when detailedinformation is not updated, the same version_number is set for theinformation. When detailed information is changed, the information mayhave a different version_number such that the metadata processor canidentify a set having updated information and determine whether toperform update. When the next RAP arrives, a scene start time changes tothe new RAP and thus sync_start can change to the new RAP and can beapplied. In this case, when a sync duration end point(sync_start+sync_duration) is not changed, the same version_number canbe applied upon determining that there is no information change.

When application information is previously transmitted before arrival ofan RAP related to a metadata application timing used in a program,application timing can be signaled through a relative concept such astime difference, order and number of frames. In this case, it may bepossible to signal that the corresponding metadata is not applied in thecorresponding RAP but will be applied later using predeterminedsignaling such as sync_start=FFFF or a method of signaling with a longerduration than an RAP.

In FIG. 8, sync_start=0 and sync_duration=180 can be set for the secondHDR_info_type=0100 in a period of 00:00:00:00 to 00:00:02:00, andsync_start=0 and sync_duration=60 can be set for the secondHDR_info_type=0100 in a period of 0:00:02:00 to 00:00:04:00. As starttime changes from 00:00:00:00 to 00:00:02:00, duration can be changedand signaled for the same information (set 1, ver 0). The receiver doesnot perform metadata update when it is confirmed that the metadata hasnot been changed.

When details of information that plays the same role as previousinformation have been changed, the broadcast transmission device canincrease version_number of common HDR metadata while maintainingset_number thereof. The metadata processor of the receiver can recognizeinformation change on the basis of changed version_number and updateprevious information to new information.

When information has been changed in the metadata in a period of00:00:04:00 to 00:00:06:00 as shown in FIG. 8, information such as starttime may be additionally delivered. When information has been changed inthe metadata, for example, when information B has been changed toinformation B′, a new version number can be assigned. It can beconfirmed from the figure that the version number for set_number=2 is 0in the period of 00:00:02:00 to 00:00:04:00 but the version number hasincreased to 1 in the period of 00:00:04:00 to 00:00:06:00. It is alsopossible to signal that update needs to be performed when expirationtime is changed.

FIG. 9 illustrates a method of signaling metadata information with timeaccording to another embodiment of the present invention. FIG. 9 shows acase in which there is transition between HDR and SDR in signaling ofmetadata information. As shown, transition of an HDR video stream to anSDR video stream occurs in the third RAP. In this case, the HDRinformation descriptor is transmitted and received no longer after thethird RAP.

When transmission of the HDR information descriptor is stopped, thebroadcast transmission device can notify the receiver that transmissionof the HDR information descriptor is stopped through transition_flag. Inthe case of transition of content DR from HDR to SDR, transmission of anSEI message delivering video properties of HDR/WCG content is stoppedand no more information may be transmitted after a content transitiontime. Although the HDR information descriptor such as mastering displayinformation, color gamut mapping and viewing condition may be used forSDR content, of course, legacy SDR content that does not use the HDRinformation descriptor can be considered in the present example. In thiscase, a transition flag on time, that is, a time at which thetransition_flag is set to 1 is important. As in the above example, thetransition_flag can be set to 0 in a frame immediately before thetransition time and the RAP (the second RAP in the figure) including theframe.

FIG. 10 illustrates dynamic_range_mapping_info according to anembodiment of the present invention. Whendynamic_range_mapping_info_type described above with reference to theupper part of FIG. 7 is set to 0x03, dynamic_range_mapping_info( ) canbe directly defined in the HDR_info descriptor. When HDR_info_type is achannel, a program or content as common HDR metadata related tomastering display or video, information described in FIG. 9 can be usedfor the entire video (channel, program or content). When HDR_info_typeis scene type or frame type as scene/frame HDR metadata, the informationdescribed in FIG. 9 can be used for a corresponding section. Fieldsincluded in dynamic_range_mapping_info( ) will be described below.

Dynamic_range_mapping_info( ) according to an embodiment of the presentinvention may include luminance_max, luminance_min, private_EOTF,number_of_coeff, transfer_curve_coeff[i], clipping_flag,linear_mapping_flag, luma_clipping_upper_bound,luma_clipping_lower_bound, luminance_upper_bound, luminance_lower_bound,luma_upper_value, luma_lower_value, mid_DR_transformation_curve_type,mid_DR_transformation_curve( ), mid_DR_percentage,upper_DR_transformation_curve_type, upper_DR_transformation_curve( ),upper_DR_percentage, lower_DR_transformation_curve_type,lower_DR_transformation_curve( ), number_luminance_upper_bound_diff,luminance_upper_bound_diff[i], luma_upper_value_diff[i],upper_DR_transformation_curve_type[i], upper_DR_transformation_curve( ),upper_DR_percentage[i] and/or mid_DR_percentage[i].

Luminance max indicates maximum reference luminance represented in UHDbroadcast content. That is, this indicates a maximum value of dynamicrange (DR). For example, in the case of a reference monitor, 100cd/m{circumflex over ( )}2 is decided as maximum reference luminance. Inthis case, 1, which is the quotient of a value obtained by dividing theabove value by 100 (decimal number) in consideration of a general range,can be transmitted.

Luminance min indicates minimum reference luminance represented in UHDbroadcast content. That is, this indicates a minimum value of thedynamic range. For example, in the case of a reference monitor, 0.05cd/m{circumflex over ( )}2 is decided as minimum reference luminance. Inthis case, 5 obtained by multiplying the above value by 100 (decimalnumber) in consideration of a general range can be transmitted.

Private EOTF indicates whether any EOTF function is used. This can bedelivered through VUI information when a widely-used EOTF such as ITU-RBT.1886, REC.709 and BT.2020 is used. However, when an EOTF which hasnot been decided as a standard is used, the corresponding field valuecan be set to 1. For example, perceptual quantization can be used as anEOTF which has not been decided as standard, that is, arbitrary EOTF.

number_of_coeff indicates the number of coefficients used for anarbitrary EOTF.

transfer_curve_coeff[i] indicates a coefficient used for an arbitraryEOTF.

clipping_flag indicates whether a clipping option is used and can have avalue of 1 when use of the clipping option is permitted.

linear_mapping_flag indicates whether a linear dynamic rangetransformation method is used. When the linear dynamic rangetransformation method is used, linear_mapping_flag has a value of 1.

luma_clipping_upper_bound indicates a digital value of an upper criticalpoint in a dynamic range (DR) displayed when the clipping option isused.

luma_clipping_lower_bound indicates a digital value of a lower criticalpoint in the dynamic range (DR) displayed when the clipping option isused.

luminance_upper_bound indicates a maximum value (in nit) of a dynamicrange that needs to be mandatorily represented among dynamic rangesrepresented in UHD broadcast content. luminance_upper_bound may be acriterion for determination of a display type of a receiving device.Further, luminance_upper_bound may signal an additional criterion fordetermination of a display type of a receiving device.

luminance_lower_bound indicates a minimum value (in nit) of a dynamicrange that needs to be mandatorily represented among dynamic rangesrepresented in UHD broadcast content. luminance_lower_bound may be acriterion for determination of a display type of a receiving device.Further, luminance_lower bound may signal an additional criterion fordetermination of a display type of a receiving device.

luma_upper_value indicates a digital value corresponding toluminance_upper_bound.

luma_lower_value indicates a digital value corresponding toluminance_lower_bound.

mid_DR_transformation_curve_type identifies a DR transformation curveused in a mid dynamic range. One of a linear curve, an exponentialcurve, an S-curve, a logarithmic curve, a combination curve and alook-up table (LUT) may be used as a transformation curve.

mid_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified bymid_DR_transformation_curve_type. For example, gradient information canbe transmitted when a linear curve is used, information on a base can betransmitted when an exponential curve or a logarithmic curve is used,information about coordinates of an inflection point and a base and ay-intercept of each section can be transmitted when an S-curve is used,and information about an x-coordinate of each section, a curve type ofeach section and the corresponding graph can be transmitted when acombination curve is used.

mid_DR_percentage indicates the percentage of a mid dynamic range amongdynamic ranges of UHD broadcast content, which occupies the entiredynamic range of a receiver display.

upper_DR_transformation_curve_type identifies a dynamic rangetransformation curve used in an upper dynamic range. One of a linearcurve, an exponential curve, an S-curve, a logarithmic curve, acombination curve and a look-up table (LUT) may be used as atransformation curve.

upper_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified byupper_DR_transformation_curve_type. For example, gradient informationcan be transmitted when a linear curve is used, information on a basecan be transmitted when an exponential curve or a logarithmic curve isused, information about coordinates of an inflection point and a baseand a y-intercept of each section can be transmitted when an S-curve isused, and information about an x-coordinate of each section, a curvetype of each section and the corresponding graph can be transmitted whena combination curve is used.

upper_DR_percentage indicates the percentage of an upper dynamic rangeamong dynamic ranges of UHD broadcast content, which occupies the entiredynamic range of a receiver display.

lower_DR_transformation_curve_type identifies a dynamic rangetransformation curve used in a lower dynamic range. One of a linearcurve, an exponential curve, an S-curve, a logarithmic curve, acombination curve and a look-up table (LUT) may be used as atransformation curve.

lower_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified bylower_DR_transformation_curve_type. For example, gradient informationcan be transmitted when a linear curve is used, information on a basecan be transmitted when an exponential curve or a logarithmic curve isused, information about coordinates of an inflection point and a baseand a y-intercept of each section can be transmitted when an S-curve isused, and information about an x-coordinate of each section, a curvetype of each section and the corresponding graph can be transmitted whena combination curve is used.

number_luminance_upper_bound_diff indicates the number of variables usedto extend a mid dynamic range.

luminance_upper_bound_diff[i] indicates a difference value forconstituting an (i+1)-th luminance value in UHD broadcast content. Whena mid dynamic range is extended in a display which has a wider dynamicrange than an existing dynamic range but cannot accommodate all dynamicranges represented in UHD broadcast content (case 2),luminance_upper_bound can be changed to a value indicated byluminance_upper_bound+luminance_upper_bound_diff[0]+ . . .+luminance_upper_bound_diff[i].

luma_upper_value_diff[i] indicates a digital value corresponding to an(i+1)-th luminance value in UHD broadcast content. When a mid dynamicrange is extended in a display which has a wider dynamic range than anexisting dynamic range but cannot accommodate all dynamic rangesrepresented in UHD broadcast content (case 2), luma_upper_value can bechanged to a value indicated byluma_upper_value+luma_upper_value_diff[0]+ . . .+luma_upper_value_diff[i].

upper_DR_transformation_curve_type[i] can identify a transformationcurve used in a changed upper dynamic range when an (i+1)-th dynamicrange is supported. That is, when a mid dynamic range is extended,upper_DR_transformation_curve_type[i] can identify a transformationcurve used in an upper dynamic range changed according to the extendedmid dynamic range.

upper_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified byupper_DR_transformation_curve_type[i]. That is,upper_DR_transformation_curve( ) indicates details of a transformationcurve used in a changed upper dynamic range when an (i+1)-th dynamicrange is supported.

upper_DR_percentage[i] indicates the percentage of a changed upperdynamic range, which occupies the entire dynamic range of a receiverdisplay, when a mid dynamic range of UHD broadcast content is changed.

mid_DR_percentage[i] indicates the percentage of a changed mid dynamicrange which occupies the entire dynamic range of a receiver display whena mid dynamic range of UHD broadcast content is changed.

FIG. 11 illustrates a case in which an SEI message defined in HEVCaccording to an embodiment of the present invention is referenced. Whencolor_gamut_mapping_info_type described in the lower part of FIG. 7 isset to 0x00, gamut_mapping_info( ) is not directly defined inHDR_video_info descriptor and the SEI message defined in HEVC can bereferred to. Here, the SEI message can comply with a color remappinginformation SEI message syntax defined in HEVC.

When HDR_info_type is a channel, a program or content as common HDRmetadata related to mastering display or video, referenced informationcan be used for the entire video (channel, program or content). WhenHDR_video_info_type is scene type or frame type as scene/frame HDRmetadata, referenced information can be applied only to a correspondingsection.

FIGS. 12 and 13 illustrate an embodiment of signaling HDR_infodescriptor according to an embodiment of the present invention through aPMT. The PMT refers to a program mapping table and may include table IDinformation, section syntax indicator information, section lengthinformation, program number information, version number information,current next indicator information, section number information, PCR_PIDinformation, program info length information, first descriptorinformation, stream type information, elementary PID information,elementary stream length (Es_info_length) information, second descriptorinformation, CRC information, etc. The first descriptor information canrefer to descriptor information included in the first loop following theprogram info length information and the second descriptor informationcan refer to descriptor information included in the second loopfollowing the Es_info_length information.

UHD_program_info_descriptor according to an embodiment of the presentinvention can be signaled by being included in the first descriptorinformation included in the PMT, and the aforementioned HDR_infodescriptor can be signaled by being included in the second descriptorinformation included in the PMT.

UHD_program_info_descriptor may include at least one of descriptor_tag,descriptor_length and UHD_service_type as shown in the upper part ofFIG. 12. Here, UHD_service_type can refer to the type of a UHD serviceas shown in the lower part of FIG. 12. For example, UHD_service_type canindicate a UHD service type designated by a user, such as UHD1(4K),UHD2(8K) or a type classified by quality. Various UHD services can beprovided to a receiver through UHD_service_type. The present inventioncan indicate provision of HDR info regarding different stages or unitssuch as video, scenes, clips or frames by setting UHD_service_type=1100(UHD1 service with HDR information metadata; an example of 4K).

FIGS. 14 and 15 illustrate an embodiment of signaling HDR_infodescriptor according to an embodiment of the present invention throughan EIT. ATSC and DVB systems may include the EIT as a signaling table.Syntaxes included in the EIT are shown in FIGS. 14 and 15.

The EIT (Event Information Table) of ATSC and DVB systems according toan embodiment of the present invention may commonly include a table_idfield, a section_syntax_indicator field, a section_length field, asource_id (service_id) field, a version_number field, acurrent_next_indicator field, a section_number field, alast_section_number field, a num_events_in_section(segment_last_section_number) field, an event_id field, a start_timefield, a length_in_seconds (duration) field, a descriptors_length field,a descriptor( ) field and/or a CRC_32 field.

The table_id field indicates that the corresponding table is an EIT(Event Information Table). The section_syntax_indicator field is a 1-bitfield which is set to 1 to indicate a long format of an MPEG-2 privatesection table. The section_length field indicates the length of a tablesection following this field in bytes. The source_id field indicates asource ID of a virtual channel carrying an event described in thecorresponding section. The version number field is a 5-bit fieldindicating a version number of the table. The current_next_indicatorfield is a 1-bit field which indicates whether the table is currentlyapplicable or applicable later. The section number field indicates asection number. The last_section_number field identifies the number ofthe last section. The num_events_in_section field indicates the numberof events included in the corresponding table section. The event_idfield identifies a specific number indicating a described event. Thestart time field indicates a start time of the corresponding event onthe basis of GPS time in seconds. A value indicating a start time of anevent may be greater than a value indicating an expiration time of anevent which is being broadcast on a virtual channel. The expiration timeof an event can be defined as the sum of the start time of the event andthe duration of the event. The length_in_seconds (duration) fieldindicates a duration of an event in seconds. The descriptors_lengthfield indicates the length of descriptor ( ) described following thisfield. The descriptor( ) is a descriptor loop located within the table.The descriptor loop may include an additional descriptor. The EIT mayinclude zero or more descriptors, and the relevant descriptor maycorrespond to an event level descriptor which describes informationapplied to each event. According to an embodiment of the presentinvention, UHD_program_info_descriptor and HDR_info descriptor can beincluded in the event level descriptor and delivered.UHD_program_info_descriptor may be used to identify a UHD service type.Whether HDR_info descriptor includes HDR video information metadata maybe checked at the event level, and HDR_video_info descriptor may be usedto determine whether a receiver can accommodate the HDR videoinformation metadata. In the case of cable broadcast, the sameinformation may be provided to an AEIT instead of the aforementioneddescriptors.

The CRC_32 field includes a CRC value used to check data integrity. TheCRC value can guarantee output of “0” from a register included in adecoder defined in Annex A of ISO-13818-1 “MPEG-2 Systems” after all EITsections are processed.

When UHD_service_type of UHD_program_info_descriptor signaled throughthe EIT is set to 1100, the receiver can confirm that information aboutan appropriate viewing condition is delivered through metadata. Forexample, when UHD_service_type is 1100, the receiver can confirm thatthe corresponding service is UHD1 service with HDR video informationmetadata, 4K.

When UHD_service_type of UHD_program_info_descriptor signaled throughthe EIT is set to 0000, the receiver can check whetherHDR_info_descriptor( ) is present and recognize provision of HDR inforegarding different stages or units such as video, scenes or frames.Here, UHD_service_type of 0000 can indicate UHD1 service.

In the above case, it is possible to determine whether information inunits of mastering display, content, scene or frame, which a contentprovider desires, can be used in a viewer's display usingHDR_info_descriptor( ) By using HDR_info_descriptor( ), it is possibleto predetermine whether content, scene or frame based metadata is usedfor content currently played or played later and a receiver can preparesetting for a situation such as scheduled recording.

FIG. 16 illustrates HDR_info_descriptor( ) according to anotherembodiment of the present invention. A plurality of pieces ofinformation may be present for one event. That is, information is notconsistently applied to content but applied information can be changedaccording to time or presence/absence of inserted content.Alternatively, various modes intended by a producer may be supported forone piece of content. Here, it is necessary to determine whether areceiver display can accommodate such modes, and information thereaboutcan be provided by a broadcast transmission device throughviewing_condition_metadata. A syntax in viewing_condition_metadata cancomply with the definition of the viewing condition descriptor of theSEI message.

HDR_info_descriptor may include at least one of descriptor_tag,descriptor_length and number_of_info as shown in the upper part of FIG.16. HDR_info_descriptor may include a loop and can include as manypieces of HDR_info_metadata( ) as the number indicated by number ofinfo. The syntax of HDR_info_metadata( ) may deliver the script or partthereof of the HDR information descriptor configuration of FIG. 4.

FIG. 17 is a block diagram of a receiver, which illustrates an operationmethod according to an embodiment of the present invention. When HDRinformation is transmitted through the aforementioned method, thereceiver analyzes a signal and applies information to HDR video on thebasis of the analyzed signal through the following process.

The receiver according to an embodiment of the present invention mayreceive a broadcast signal from a radio frequency (RF) channel using atuner and a demodulator 1601. The broadcast signal may be receivedthrough other paths (not shown) as well as an RF channel. For example,the broadcast signal can be received through IP basedbroadcast/communication, wired/wireless communication and wired/wirelessinterfaces. Further, the broadcast signal and metadata which will bedescribed below may be received through different paths. The metadatawhich will be described below may be transmitted and received throughother paths (e.g., IP based broadcast/communication, wired/wirelesscommunication, wired/wireless interfaces, short-range wirelesscommunication, etc.) as well as broadcast signals.

The receiver may decode the received broadcast signal using a channeldecoder 1602. Here, the channel decoder may decode the broadcast signalusing VSB or QAM. The decoded broadcast signal may be demultiplexed intobroadcast content data and signaling data by a demultiplexer 1603. Thebroadcast content data may include HDR video data and may be decoded bya video decoder 1605. The signaling data may include information aboutthe broadcast content data and include a signaling table or signalinginformation such as a PMT, a VCT, an EIT or an SDT according to anembodiment. The receiver may extract UHD_program_info_descriptor fromthe signaling information (e.g., a PMT) using a section data processor1604.

The receiver checks whether there are additional services or media thatthe receiver needs to additionally receive in order to constituteoriginal UHDTV broadcast using UHD_program_info_descriptor. In anembodiment of the present invention, the receiver can recognize presenceof additional information through an SEI message upon reception ofUHD_service_type=1100. Alternatively, the receiver can recognizepresence of video related additional information through an SEI messageusing an EIT upon receiving UHD_service_type=0000 (8K is 0001).

Upon confirmation of presence of additional information, the receivercan recognize whether a range to which the additional information isapplied is a channel, a program, content, a scene, a clip or a frame onthe basis of the HDR information SEI message or HDR_info_type. Inaddition, HDR_info_descriptor( ) can include information about the starttime and expiration time of the additional information forsynchronization of the additional information range for each case. In anembodiment, sync_info_type, sync_start and sync_duration which areinformation for synchronization on the basis of a video frame are used.Further, HDR_info_descriptor( ) can include transition flag indicatingHDR end time.

When HDR_video_info_type is information applied to entire content,signaling information can signal whether information in units of scene,clip or frame is additionally provided throughHDR_video_enhancement_info_present_type. Accordingly, the receiver canrecognize that information in units of scene, clip or frame is providedin advance and prepare settings for metadata processing in units ofscene, flip or frame and HDR video quality enhancement.

The receiver may recognize the type of information regarding highcontrast or information representing luminance as information capable orrepresenting a dynamic range through signaling information usingdynamic_range_info_type. For example, dynamic_range_info_type canindicate an aspect ratio and f-stop as high contrast information andindicate peak luminance and minimum luminance as luminance information.A value according to each type may be delivered to the receiver throughdynamic_range_info_value[i]. Particularly, according to an embodiment ofthe present invention, dynamic ranges according to characteristics ofcontent, mastering display, a frame and a scene can be represented, andluminance can be subdivided and represented throughdynamic_range_info_type. In addition, the receiver can recognize an EOTFtype, a color gamut type and a color temperature type used for colorencoding through transfer_function_type, color_gamut_type andcolor_temperature_type.

HDR_info_descriptor( ) is additional information which provides dynamicrange mapping, color gamut mapping and viewing condition information tothe receiver. When various additional information provision methods areavailable, an SEI message defined in HEVC or a predetermined SEI messagemay be designated for each method throughdynamic_range_mapping_info_type, color_gamut_mapping_info_type andviewing_condition_info_type. When additional information is directlydefined in HDR_info descriptor, the receiver can recognize detailedinformation through dynamic_range_mapping_info( ),color_gamut_mapping_info( ) and viewing_condition_info( ).

The aforementioned signaling information may be stored in a metadataprocessor 1606 of the receiver. The stored signaling information may beupdated when the aforementioned set number or version is changed. Thereceiver may synchronize video quality enhancement information(signaling information) stored in the metadata processor 1606 with videodata using a synchronizer 1607 such that the video quality enhancementinformation can be applied to the video data according to an applicationunit.

The receiver may deliver dynamic range information in units of content,scene or frame to an HDR algorithm or a video quality enhancement unitsuch as an existing post processor 1608 (post-processing module) on thebasis of information provided thereto, to achieve video qualityenhancement. In addition, when there is detailed information related todynamic range mapping, color gamut mapping and viewing conditioninformation, the receiver may directly connect related modules such astone mapping, color mapping, color correction and white balance modulesto achieve video quality enhancement. If video processing is performedin a linear luminance domain in the receiver, EOTF recognized throughtransfer_function_type can be applied.

The receiver may display post-processed HDR video through a display unit1609 to provide the HDR video to a user.

FIG. 18 is a block diagram of a broadcast transmitter according to anembodiment of the present invention. A broadcast transmitter 1701according to the present invention may include an encoder 1702, amultiplexer 1703 and/or a transmission unit 1704.

The resolution of video data input to the broadcast transmitter 1704 maybe UHD. Metadata input to the broadcast transmitter 1701 may includevideo quality enhancement metadata with respect to UHD video. Asdescribed above with reference to FIGS. 4 to 7, the video qualityenhancement metadata may include HDR_info_descriptor ( ) and informationnecessary for UHD video quality enhancement. The information necessaryfor UHD video quality enhancement may be applied to the entire content(channel, program and content) or applied on a scene-by-scene,clip-by-clip or frame-by-frame basis and may include common HDR metadataapplied to the entire content and scene/frame HDR metadata applied on ascene-by-scene, clip-by-clip or frame-by-frame basis. Further,HDR_info_descriptor( ) can include transition flag indicating HDR endtime.

The video data input to the broadcast transmitter 1701 may be encoded bythe encoder 1702. A transmission end may use HEVC (High Efficiency VideoCoding) as a video data encoding scheme. The transmission end maysynchronize the encoded video data with the video quality enhancementmetadata and multiplex the synchronized data using the multiplexer 1703.The video quality enhancement metadata may further includesynchronization information. The video quality enhancement metadata mayinclude synchronization information such as time, a time difference,start order, a POC, a PTS and the number of accumulated frames accordingto synchronization methods.

The transmission unit 1704 may transmit a transport stream output fromthe multiplexer 1703 as a broadcast signal. Here, the transport streammay be channel-coded and modulated and then transmitted as a broadcastsignal. According to another embodiment of the present invention, themetadata may be transmitted through other paths (e.g., IP basedbroadcast/communication, wired/wireless communication, wired/wirelessinterfaces and short-range wireless communication) as well as thebroadcast signal. Further, the metadata may be transmitted through adifferent path from a path through which video data is transmitted.

FIG. 19 is a block diagram of a broadcast receiver according to anembodiment of the present invention. A broadcast receiver 1801 accordingto the present invention may include a reception unit 1802, ademultiplexer 1803 and/or a decoder 1804.

A broadcast signal received by the reception unit 1802 may bedemodulated and then channel-decoded. The channel-decoded broadcastsignal may be input to the demultiplexer 1803 to be demultiplexed into avideo stream and video quality enhancement metadata. The metadata may bereceived through other paths (e.g., IP based broadcast/communication,wired/wireless communication, wired/wireless interfaces and short-rangewireless communication) as well as the broadcast signal. The output ofthe demultiplexer may be input to the decoder 1804. The decoder mayinclude a video decoder and a metadata processor. That is, the videostream can be decoded by the video decoder and the video qualityenhancement metadata can be decoded by the metadata processor. Thedecoded video stream and video quality enhancement metadata may be usedfor UHD video quality enhancement by the post processor, as describedwith reference to FIG. 16. The receiver can post-process the decodedvideo signal on the basis of the video quality enhancement metadata andenhance video quality of the video data for at least one of HDR and WCG.

FIG. 20 illustrates a method of transmitting a broadcast signalincluding video quality enhancement metadata according to an embodimentof the present invention. The method of transmitting a broadcast signalincluding video quality enhancement metadata may include a step S1910 ofencoding a video stream to generate video data, a step S1920 ofgenerating a broadcast signal including the generated video data andvideo quality enhancement metadata, and a step S1930 of transmitting thegenerated broadcast signal.

In step S1910 of encoding a video stream to generate video data, a UHDvideo stream may be received and encoded to generate video data. Here,the video stream may be encoded using HEVC (High Efficiency VideoCoding). In step S1910 of generating video data, the video qualityenhancement metadata may be generated. As described above, the broadcasttransmission device can generate the video quality enhancement metadatawhich is applied to entire content (channel, program and content), ascene, a clip or a frame of the video data in step S1910 of generatingthe video data. The video quality enhancement metadata may be data withrespect to at least one of HDR and WCG and may have different quantitiesof information depending on application units. The video qualityenhancement metadata may be included in the HDR_info_descriptor( ) andtransmitted. Further, HDR_info_descriptor( ) can include transition_flagindicating HDR end time. In addition, the video quality enhancementmetadata may be directly defined in signaling information or generatedby referring to another message. Such video quality enhancement metadatamay be reference data used for the receiver to enhance video quality ofvideo data according to application unit. Consequently, the receiver candynamically enhance video quality of video data using the video qualityenhancement metadata received along with the video data.

In step S1920 of generating a broadcast signal including the generatedvideo data and video quality enhancement metadata, a broadcast signalframe may be built and modulated to generate a broadcast signal.

In step S1930 of transmitting the generated broadcast signal, atransport stream may be transmitted as the broadcast signal.

FIG. 21 illustrates a method of receiving a broadcast signal includingvideo quality enhancement metadata according to an embodiment of thepresent invention. The method of receiving a broadcast signal includingvideo quality enhancement metadata may include a step S2010 of receivinga broadcast signal, a step S2020 of demultiplexing the receivedbroadcast signal into video data and video quality enhancement metadataand a step S2030 of decoding and applying the video data and the videoquality enhancement metadata.

In step S2010 of receiving a broadcast signal, the broadcast signal maybe received using a reception unit, demodulated and thenchannel-decoded. The broadcast signal may include a UHD broadcast signaland may further include video quality enhancement metadata with respectto UHD broadcast content. The video quality enhancement metadata hasbeen described in detail with reference to FIGS. 4 to 15.

In step S2020 of demultiplexing the received broadcast signal into thevideo data and the video quality enhancement metadata, thechannel-decoded broadcast signal may be demultiplexed into the videodata and the video quality enhancement metadata using a demultiplexer.The video data may include UHD video data and the video qualityenhancement metadata may include HDR or WCG related data applied to theUHD video data. The video quality enhancement metadata may be includedin the HDR_info_descriptor( ) and transmitted. Further, theHDR_info_descriptor( ) can include transition_flag indicating HDR endtime. Here, the video quality enhancement metadata may be divided intocommon HDR metadata and scene/frame HDR metadata according toapplication range thereof. The video quality enhancement metadata mayinclude at least one of the common HDR metadata and the scene/frame HDRmetadata. The common HDR metadata may be information applied to allchannels, all programs or all video data constituting one piece ofcontent and the scene/frame HDR metadata may be data applied to somescenes, clips or frames of the video data. The video quality enhancementmetadata may be directly defined in signaling information of thebroadcast signal or a previously defined message may be referred to.

In step S2030 of decoding and applying the video data and the videoquality enhancement metadata, the video data may be decoded using avideo decoder to acquire the video data. In this step, the video qualityenhancement metadata can be acquired using a signaling data parser or ametadata decoder. The receiver can enhance video quality of the decodedvideo data on the basis of the video quality enhancement metadata. Thevideo quality enhancement metadata may include HDR or WCG informationregarding the video data and may further include synchronizationinformation indicating an information application time. The videoquality enhancement metadata may be applied to the video data on thebasis of the synchronization information. Accordingly, video qualityenhancement can be applied to all video data or applied per section. Auser can be provided with UHD content with enhanced video qualitythrough HDR or WCG information additionally applied to previous UHDcontent.

Although the description of the present invention is explained withreference to each of the accompanying drawings for clarity, it ispossible to design new embodiment(s) by merging the embodiments shown inthe accompanying drawings with each other. Additionally, if a recordingmedium readable by a computer, in which programs for executing theembodiments mentioned in the foregoing description are recorded, isdesigned by those skilled in the art, this is within the scope of theappended claims and their equivalents.

An apparatus and method according to the present invention may benon-limited by the configurations and methods of the embodimentsmentioned in the foregoing description. In addition, the embodimentsmentioned in the foregoing description may be configured in a manner ofbeing selectively combined with one another entirely or in part toenable various modifications.

In addition, a method according to the present invention may beimplemented with processor-readable code in a processor-readablerecording medium provided to a network device. The processor-readablemedium may include all kinds of recording devices capable of storingdata readable by a processor. The processor-readable medium may includeone of ROM, RAM, CD-ROM, magnetic tapes, floppy disks, optical datastorage devices, and the like for example and also include acarrier-wave type implementation such as a transmission via Internet.Furthermore, as the processor-readable recording medium is distributedto a computer system connected via network, processor-readable code maybe saved and executed according to a distributed system.

It will be appreciated by those skilled in the art that variousmodifications and variations may be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both the product invention and the process invention are described inthe specification and the description of both inventions may besupplementarily applied as needed.

MODE FOR INVENTION

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

The present invention can be used for broadcast and video signalprocessing and is reproducible and industrially applicable.

What is claimed is:
 1. A method for transmitting a broadcast signal by abroadcast signal transmission device for transmitting a broadcastsignal, comprising: generating, by an encoder, video data, thatcorrespond to enhanced HDR (High Dynamic Range) content or SDR (StandardDynamic Range) content, based on an access unit; multiplexing, by amultiplexer, the video data and metadata for enhanced HDR content, themetadata for enhanced HDR content including HDR information type forindicating a unit to which the metadata applies and transition flag forindicating whether a transition from the enhanced HDR content to the SDRcontent occurs such that a receiver is able to turn off a module relatedto HDR information descriptor when the transition flag is set to 1 for alast frame; and transmitting, by a transmitter, the broadcast signalincluding the multiplexed video data and metadata.
 2. The methodaccording to claim 1, wherein the metadata includes high dynamic range(HDR) information or wide color gamut (WCG) information.
 3. The methodaccording to claim 2, wherein the HDR information or the WCG informationis applied in units of channel, program or content.
 4. The methodaccording to claim 3, wherein the HDR information or the WCG informationis applied to some sections of the video data in units of scene, clip orframe.
 5. The method according to claim 2, wherein the metadata furtherincludes synchronization information indicating a start time when theHDR or the WCG information is applied to the video data.
 6. The methodaccording to claim 2, wherein the metadata further includes signalinginformation indicating termination of application of the HDRinformation.
 7. A method for receiving a broadcast signal by anapparatus for receiving a broadcast signal, comprising: receiving thebroadcast signal including video data, the video data corresponding toenhanced HDR (High Dynamic Range) content or SDR (Standard DynamicRange) content and being generated based on an access unit;demultiplexing the broadcast signal into the video data and metadata forenhanced HDR content, the metadata for enhanced HDR content includingHDR information type fir indicating a unit to which the metadata appliesand transition flag for indicating whether a transition from theenhanced HDR content to the SDR content occurs such that the apparatusfor receiving the broadcast signal is able to turn off a module relatedto HDR information descriptor when the transition flag is set to 1 for alast frame; decoding the video data and the metadata for enhanced HDRcontent; and applying the metadata for enhanced HDR content to the videodata.
 8. The method according to claim 7, wherein the metadata includeshigh dynamic range (HDR) information or wide color gamut (WCG)information.
 9. The method according to claim 8, wherein the HDRinformation or the WCG information is applied in units of channel,program or content.
 10. The method according to claim 9, wherein the HDRinformation or the WCG information is applied to some sections of thevideo data in units of scene, clip or frame.
 11. The method according toclaim 8, wherein the metadata further includes synchronizationinformation indicating a start time and duration when the HDR or the WCGinformation is applied to the video data.
 12. The method according toclaim 8, wherein the metadata further includes signaling informationindicating termination of application of the HDR information.
 13. Abroadcast signal transmission device comprising: an encoder to generatevideo data, that correspond to enhanced HDR (High Dynamic Range) contentor SDR (Standard Dynamic Range) content, based on an access unit; amultiplexer to multiplex the video data and metadata for enhanced HDRcontent, the metadata for enhanced HDR content including HDR informationtype for indicating a unit to which the metadata applies and transitionflag for indicating whether a transition from the enhanced HDR contentto the SDR content occurs such that a receiver is able to turn off amodule related to HDR information descriptor when the transition flag isset to 1 for a last frame; and a transmitter to transmit the broadcastsignal including the multiplexed video data and metadata.
 14. Abroadcast signal reception device comprising: a receiver to receive abroadcast signal including video data, the video data corresponding toenhanced HDR (High Dynamic Range) content or SDR (Standard DynamicRange) content and being generated based on an access unit; ademultiplexer to demultiplex the broadcast signal into the video data,and metadata for enhanced HDR content, the metadata for enhanced HDRcontent including HDR information type for indicating a unit to whichthe metadata applies and transition flag for indicating whether atransition from the enhanced HDR content to the SDR content occurs suchthat the broadcast signal reception device is able to turn off a modulerelated to HDR information descriptor when the transition flag is set to1 for a last frame; a decoder to decode the video data and the metadatafor enhanced HDR content; and a post processor to apply the metadata forenhanced HDR content to the video data.